Saracens director of rugby Mark McCall revealed this week that one element of his team selection for Saturday's Aviva Premiership was settled playground style. Neil de Kock and Richard Wigglesworth tossed a coin to decide who would start at scrum-half, with the coaches unwilling to choose a favourite at this stage in the season. With their plight in mind, we've selected a few other players who were forced to share the load in Scrum Sevens.

Waugh, the Waratahs skipper and for a number of years one of the world's finest flankers, had good reason to be glad when George Smith packed his bags for Toulon last summer, although the exit of his long-time rival did not pave the way to a renewed Test career as he may have hoped. Between 2001 and 2009 Smith played 110 times for the Wallabies and was often cited as the only player on the world stage who could go toe-to-toe with All Blacks skipper Richie McCaw. During a similar timeframe Waugh was capped 79 times. A strong innings, but perhaps not what he could have expected had he been born up north. On a number of occasions the duo were paired in the back-row - notably the 2003 Rugby World Cup Final - but often the nugget Waugh was left in a queue. With the World Cup nearing and his inspirational leadership still a huge factor for New South Wales, we're puzzled as to why he hasn't been drafted back in at Test level. As back-up to David Pocock. It never rains, it pours.

All too often it has been a case of 'out of sight, out of mind' in the case of Murphy. A prodigiously talented player - with an unfortunate knack of poorly-timed injuries - his status as a living legend at Leicester led to him often holding the door open for Girvan Dempsey, the Leinsterman who was the epitome of solid. Two great players vying for one position is what's known in some quarters as strength in depth, but it's easy to wonder whether the shoe may have been on the other foot had it been Dempsey turning out at Welford Road. He won 82 caps before calling time last year - 11 more that Murphy, whose tally also includes two for the British & Irish Lions.

For Hopkins, the Maesteg scrum-half tasked with breaking into the Wales side ahead of Gareth Edwards, the toss of a coin for a start would have been a welcome relief. Capped twice, once by Wales against England in 1970 and once by the Lions in New Zealand a year later, both of his caps were as a replacement for Edwards in an age where players only left the field when they'd lost a limb. As the 1970s wore on, Brynmor Williams also learned about life in Edwards' considerable shadow and made his Test bow for the Lions in 1977, when Wales' incumbent had opted out due to work commitments. Williams would also have a battle on his hands when Edwards called it a day in 1978, with the giant Cardiff No.9 Terry Holmes emerging from stage right to snatch the jersey.

Being the able deputy to the world's most-capped player is an unenviable task, and one that fell to New South Wales' Chris Whitaker during the reign of George Gregan as Australia scrum-half. Capped 31 times across a seven-year Test career, Whitaker only wore No.9 on his back five times, making him the most-capped replacement in international rugby. At provincial level, the opposite was true and he held the Waratahs caps record until leaving for Europe, at which point Waugh took over at the top of the charts. Such was Gregan's dominance that only six players started at scrum-half for the Wallabies between 2000 and 2009 - Gregan, Whitaker, Sam Cordingley, Luke Burgess, Matt Giteau and Will Genia.

Carter's new four-year deal to remain an All Black is a major coup for the New Zealand Rugby Union (NZRU), but it does conjure the spectre of another generation of playmakers passing under the radar at international level. The queue behind Carter for an All Blacks jumper is long - in recent seasons Stephen Donald, Aaron Cruden, Mike Delany and Colin Slade have all had runs at No.10 - but perhaps the most notable case of talent being railroaded overseas involved Blues fly-half Nick Evans, who upped sticks for Harlequins in 2008. Arguably the best in the north since his switch, his relatively meagre tally of 16 Tests, three at fullback, would have been tripled had he been from any other nation. Still, it's hard to look past the best 10 in the world, so the NZRU can hardly be blamed for their decision.

On current form, there's no contest. Du Plessis is currently out-playing his seasoned rival, but again he looks set to lose out on the Springboks' No.2 jersey for at least part of this season due to the inspirational leadership of his Sharks team-mate Smit. At Super Rugby level, Smit has been rotated across the front-row, a ploy that is unlikely to translate at international level according to coach Peter De Villiers. To date Du Plessis has won 14 caps off the bench in his career and will not be too keen on adding to that number given his status in the world game. The Boks just can't look past Smit, however. It could be argued that Du Plessis, Saracens' Schalk Brits and Leinster's Richardt Strauss are three of the sport's finest hookers, yet only one of them will be involved at international level this year. How often he is will be a big call for the management, and one that could end one of rugby's greatest Test careers.

During Wales' run to a Six Nations Grand Slam, Warren Gatland employed a rotation system at fly-half, chopping and changing between James Hook and Stephen Jones. Hook began the tournament with two touchline conversions against England and a try-scoring display against Scotland, being replaced by Jones for a rout of Italy. Gatland then kept faith with the veteran for a pivotal away match against Ireland - throwing the cat among the pigeons for those who had written off Jones. Hook returned for the Slam decider against France but lost out in the long run, with Jones dominating the fly-half berth in the following two years - including three Tests for the Lions. Hook's return to No.10 against Scotland in the 2011 Six Nations was again hailed as a decisive change - proof of Jones' longevity if ever there was one. Both Ireland (Jonny Sexton and Ronan O'Gara) and England (Toby Flood and Jonny Wilkinson) now have similar game-plans.